Wu Kan, Li Xiaohui, Wang Yonggang, Wang Qi Jie, Shum Perry Ping, Chen Jianping
Opt Express. 2015 Jan 12;23(1):501-11. doi: 10.1364/OE.23.000501.
We investigate the timing phase noise of fiber lasers mode locked by graphene oxide (GO) and carbon nanotubes (CNTs), respectively, integrated in a linear cavity fiber laser in the reflecting operation. Due to the shorter decay time of the GO and CNTs, weaker slow saturable absorber effects are expected and mode-locked lasers based on these two saturable absorbers exhibit low excess timing phase noise coupled from the laser intensity noise. Compared with a reference laser mode locked by semiconductor saturable absorber mirror (SESAM), GO based laser obtains a timing phase noise reduction of 7 dB at 1 kHz and a timing jitter reduction of 45% experimentally whereas CNTs based laser obtains a timing phase noise reduction of 3 dB and a timing jitter reduction of 29%. This finding suggests that saturable absorbers with short decay time have the potential for achieving mode locking operation with low timing phase noise, which is important for applications including frequency metrology, high-precision optical sampling, clock distribution and optical sensing.
我们分别研究了集成在线性腔光纤激光器反射操作中的、由氧化石墨烯（GO）和碳纳米管（CNT）锁模的光纤激光器的定时相位噪声。由于GO和CNT的衰减时间较短，预计其慢饱和吸收效应较弱，基于这两种饱和吸收体的锁模激光器表现出由激光强度噪声耦合的低过量定时相位噪声。与由半导体可饱和吸收镜（SESAM）锁模的参考激光器相比，基于GO的激光器在实验中在1 kHz处实现了7 dB的定时相位噪声降低和45%的定时抖动降低，而基于CNT的激光器实现了3 dB的定时相位噪声降低和29%的定时抖动降低。这一发现表明，具有短衰减时间的饱和吸收体具有实现低定时相位噪声锁模操作的潜力，这对于包括频率计量、高精度光学采样、时钟分配和光学传感在内的应用非常重要。
